Ring 3 multitasking

src/kernel/process.h

@@ -0,0 +1,30 @@
+#ifndef PROCESS_H
+#define PROCESS_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+// Registers saved on the stack by interrupts/exceptions
+typedef struct {
+    uint64_t r15, r14, r13, r12, r11, r10, r9, r8;
+    uint64_t rbp, rdi, rsi, rdx, rcx, rbx, rax;
+    uint64_t int_no, err_code;
+    uint64_t rip, cs, rflags, rsp, ss;
+} __attribute__((packed)) registers_t;
+
+typedef struct process {
+    uint32_t pid;
+    uint64_t rsp; // Current stack pointer representing context
+    uint64_t pml4_phys; // Physical address of the page table
+    uint64_t kernel_stack; // Ring 0 stack pointer for user mode switches
+    bool is_user;
+    struct process *next;
+} process_t;
+
+void process_init(void);
+void process_create(void* entry_point, bool is_user);
+process_t* process_get_current(void);
+uint64_t process_schedule(uint64_t current_rsp);
+
+#endif
+